Some changes to the floor plan with a cockpit crew lavatory would do it.
Ever looked at the layout of an a320 or similar airplane.... I bet not. One toilet in front, two (or one) in the back, the rest filled with seats. So you would lose at least two rows of seats. Totally impracticle, nor cost efficient. They are eliminating toilets not creating additional ones.
Giving the pilots a bedpan could work... And hope nobody gets hit on the head with it or gets crazy on landing.